CVE-2006-4272 in vBulletin
Summary
by MITRE
** DISPUTED ** Jelsoft vBulletin 3.5.4 allows remote attackers to register multiple arbitrary users and cause a denial of service (resource consumption) via a large number of requests to register.php. NOTE: the vendor has disputed this vulnerability, stating "If you have the CAPTCHA enabled then the registrations wont even go through. ... if you are talking about the flood being allowed in the first place then surely this is something that should be handled at the server level."
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability described in CVE-2006-4272 pertains to Jelsoft vBulletin version 3.5.4, a widely used bulletin board system that was prevalent in web application security discussions during the mid-2000s. This issue involves a potential denial of service condition that could be exploited by remote attackers through excessive user registration requests. The vulnerability operates at the application layer of the OSI model, specifically targeting the user registration functionality of the forum software, which represents a critical component in maintaining system integrity and resource management. The flaw allows malicious actors to flood the registration endpoint with numerous requests, potentially leading to resource exhaustion and service disruption for legitimate users attempting to access the platform.
The technical implementation of this vulnerability exploits the lack of adequate rate limiting or flood protection mechanisms within the registration.php script. When an attacker sends a large volume of registration requests to the vulnerable system, the application processes each request without sufficient validation or throttling controls. This behavior creates a scenario where the server's computational resources become consumed disproportionately by these registration attempts, effectively denying service to legitimate users. The vulnerability demonstrates a weakness in input validation and access control mechanisms, as it allows unauthenticated users to perform actions that should be restricted or monitored. From a cybersecurity perspective, this represents a classic resource exhaustion attack pattern that can be categorized under common attack vectors documented in various threat modeling frameworks.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall security posture of the affected system. While the vendor disputed the severity of the issue, citing CAPTCHA as a mitigating factor, this response highlights a fundamental security principle that authentication mechanisms should not be solely relied upon for protection against automated attacks. The vulnerability exposes weaknesses in the application's defensive architecture, particularly in how it handles concurrent requests and manages user registration workflows. From an attacker's perspective, this vulnerability could be leveraged as part of a broader attack strategy to degrade service availability or to create conditions that facilitate other types of exploitation. The issue also demonstrates the importance of implementing proper server-level protections as recommended by the vendor, since application-level controls alone may prove insufficient against determined attackers.
The disputed nature of this vulnerability by the vendor introduces interesting considerations regarding security assessment methodologies and the responsibility of software vendors in addressing potential threats. The vendor's response suggests that the vulnerability may not exist under normal operational conditions when CAPTCHA mechanisms are properly configured, which aligns with security best practices outlined in various industry standards including those referenced in the CWE database. However, this response also raises questions about the completeness of security testing and the potential for attackers to exploit configurations that may not be immediately obvious to system administrators. The vulnerability serves as an example of how security controls must be layered and validated across multiple points in a system's architecture, rather than relying on any single protection mechanism. From an ATT&CK framework perspective, this vulnerability would be classified under the resource exhaustion category and could be relevant to techniques related to service availability compromise, demonstrating the importance of implementing robust rate limiting and monitoring mechanisms at both application and network levels.